1. Field of the Invention
The present invention relates to an endoscope hood attached to the distal end of an endoscope.
2. Description of the Related Art
When an internal cavity is observed using an endoscope, it sometimes happens that the objective lens at the distal end of the endoscope cannot be sufficiently away from a target object. To observe such an object, an endoscope hood having a substantially cylindrical shape is attached to the distal end of the insertion section of the endoscope. The hood is positioned between the target object and the objective lens disposed at the distal end of the endoscope. By so doing, a predetermined distance is maintained between the distal end of the endoscope and the target object, and reliable observation using the endoscope is thus enabled.
When the endoscope is being inserted into a body cavity or when it is being used for observation or treatment in the body cavity, the endoscope hood must not fall off the endoscope. As a measure for preventing the endoscope hood from falling off, the conventional art uses a tape. Specifically, after the endoscope hood is attached to the endoscope, the tape is wound around the attachment portion of the endoscope hood.
However, such a tape-winding operation takes time and very troublesome. In addition, since the tape-wound portion is inevitably thick, the endoscope may not be easily inserted into a body cavity.
In recent years, making an endoscope hood of an elastic material has come to be adopted as a measure for preventing the hood from falling off. The endoscope hood is forcibly fitted with the distal end of the microscope, utilizing the elasticity. In this case, the endoscope hood is provided with a fitting portion of sufficient length. When the fitting portion of the endoscope hood is elastically fitted with the distal end of the endoscope, with a sufficient length maintained, the endoscope hood is reliably prevented from falling off the endoscope body.
However, if the endoscope hood is elastically fitted with the distal end portion of the endoscope by force, it cannot be easily removed from the distal end of the endoscope. To be more specific, the endoscope hood may have to be removed from the endoscope by elastically deforming the endoscope hood by force and detaching it from the endoscope. Since the endoscope is subject to strong force then, it may be damaged.
The endoscope hood can be removed from the endoscope by engaging a fingernail with the distal end of the fitting portion of the endoscope hood and pulling the endoscope hood away from the endoscope. The endoscope hood can be removed by pulling the endoscope hood in the direction opposite to the fitting direction by means of a tool and separating the endoscope hood from the endoscope body. In such cases, however, the surfaces of the endoscope may be damaged.
The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an endoscope hood which does not fall off the distal end of the endoscope after being fitted therewith, and which can be easily detached from the endoscope without giving damage to the endoscope.